Werner Becker MPE
Title:
Pulsars - cosmic beacons seen by ROSAT
Abstract:
Neutron stars are among the most fascinating astronomical objects
in the universe. Born in the imploding core of a supernova, they
provide a unique class of stellar objects with properties that
make them nearly ideal probes for investigating a wide variety
of physical problems. Currently, nearly 800 neutron stars are known
as rotation-powered pulsars. In the course of the ROSAT and ASCA
mission, about 10\% of them have been observed in detailed pointed
observations, leading to the detection of pulsed X-ray emission from
15 of them while 18 more pulsars are identified only by positional
coincidence with a radio pulsar.
One primary goal addressed with ROSAT was to search for thermal X-ray
emission from cooling neutron stars. The close link between the thermal
evolution of neutron stars and the physical characteristics of neutron
star material at super-nuclear densities provides an important starting
point for the empirical study of matter at extreme energies and baryon
densities. Comparing the neutron star temperatures and temperature
upper limits measured by ROSAT with the theoretical predictions based
on different equations of state thus provides the empirical basis
essential for the verification of neutron star models and cooling
theories.